1. Field of the Invention
The present invention relates generally to data exchange and processing thereof; more particularly, the present invention relates to a method and apparatus where a source delivers graphics data to a target, which receives and displays the graphics data, particularly where the source of the graphics data controls how the graphics data is to be displayed at the target.
2. Background of Related Art
Nowadays, a plethora of products exist for receiving and/or displaying video signals, e.g., television broadcasting stations, satellite broadcasting services, video feed services, or the like. These video signal receiver products may range from products that receive and process video signals only in analog form, to products that receive and process video signals in digital form, and to products that are capable of receiving and processing video signals in analog and digital form. Some products are equipped with other integrated features, e.g., recording capabilities, or the like. The available features for displaying (e.g., picture-in-picture (PIP), picture-in-graphics (PIG), double screen, or the like) the video signal also vary widely among the products.
There are equally diverse products or sources for delivering the video signals, e.g., over-the-air broadcasting stations, cable operators, direct satellite services, live video feed services, or the like. Many of these sources send, in addition to the video signals, graphics data to be displayed at a receiver for providing programming guide, advertisement, value added services (e.g., stock quotes, news service, etc.), or the like. Graphics data can be in any visual form, e.g., a text, a still picture, an interactive menu screen, or the graphics data may itself be another video stream.
For example, FIG. 1A shows a conventional video/graphics data transmission and reception arrangement 100, where a source of video signal, an AV source 101 sends graphics data together with the video signal to a receiver product, e.g., an AV target 102. Conventionally, the graphics data and video signal are combined by a mixer 104 in the AV target 102, and the combined signal is sent to a display 103, which provides a display of the graphics data and/or the video to a viewer.
However, in the conventional video/graphics data transmission and reception system thus described, because the A/V source 101 does not send information regarding how the video and graphics data are to be combined, the A/V target 102 must decide how the graphics data is to be displayed, particularly in relation to the video signal, which may be simultaneously displayed with the graphics data. Thus, the mixer 104 combines the received video signal and the graphics data without knowing how the source of the graphics data, e.g., the A/V source 101, intended to display the graphics data. The mixer 104 typically resorts to the most simple method of combining the two signals, e.g., simple overlaying, even if the AV target 102 is capable of more advanced display features, e.g., the PIP, PIG, Double Screen, or the like.
Specifically, in the case of a digital television (DTV), which may be, e.g., connected to a set-top-box (STB) via an IEEE1394 serial interface (as specified by “IEEE 1394, Standard for High Performance Serial Bus”, published 1995, which is incorporated herein by reference), the DTV receives the graphics data and the video signal (i.e., an MPEG transport stream) from an STB. The transmission of the video signal and the graphics data is governed by standards, e.g., in the United States, The Electronics Industries Alliance (EIA) Standards, EIA-775-A, “DTV 1394 Interface Specification,” published April 2000, and/or EIA-799, “On Screen Display Specification,” published June 1999, both of which are incorporated herein by reference. Because these standards do not provide means for the STB to send control information with respect to the manner in which the graphics combined with the video signal or by itself are to be displayed, the task of deciding how the two displays are to be proportioned and combined with respect to each other is nevertheless still left up to the receiver product, i.e., the DTV.
The existing standards at best provide overlaying the graphics data display over the video display by allowing specifications of “pixel definition,” which may define the location, size, and gain factors of pixels for the graphics data, and thereby allow simultaneous display and blending of the two displays, i.e., by attenuating the graphics data so as to make the graphics data appear somewhat transparent in the foreground with the video display visible in the background. The pixel definition, however, is part of the graphics data, and does not define the relationship between the video display and the graphics display. Moreover, these conventional systems heretofore do not allow the source of the graphics data to specify how the video display is to be proportioned in relation to the graphics data display. Accordingly, despite the fact that many conventional digital television sets are capable of advanced display features, e.g., the PIP, PIG, Double Screen, chroma keying, color keying, or the like, these features are not utilized to allow the DTV to know how the graphics data is intended to be displayed. Thus, the DTV in a conventional system typically performs a simple overlaying of one display, e.g., the graphics, over the other display, e.g., the video signal, and the graphics data/video signal is displayed as shown in FIGS. 1A and 1B.
Thus, the receiver product may display 105 only the graphics data over the entire screen as shown in FIG. 1B, or at best simultaneously display 106, 107 the graphics data and the video signal in a manner in which the graphics display covers, and thus, obscuring a portion of the video display as shown in FIG. 1C.
The above-described conventional graphics/video transmission and display method and system do not utilize available display features of the receiver/display product, and thus, do not provide the most effective and the most user-friendly display of the graphics/video.
Moreover, the conventional method and system heretofore does not allow the source of the graphics data, which can determine a most desirable way in which the graphics data is to be displayed to specify how the graphics data display is to be proportioned with respect to the video display to be presented to a viewer.
Thus, there is a need for a system and method of transmitting and displaying graphics data that allow a user-friendly display of graphics data with the most efficient utilization of the display capabilities of the receiver/display product.
There is also a need for a system and method of transmitting and displaying graphics data that allow the source of the graphics data to determine, at least in part, how the graphics data is to be proportioned in relation to the video display and ultimately displayed to a viewer.